Suspension device and shock absorber for vehicles



March 1951 P. w. THORNHILL ET AL SUSPENSION DEVICE AND suocx ABSORBER FOR VEHICLES Filed Sept. 16, 1949 Mm Ziwv v ha i erre ipliiera. surieceof thezri t,

Patented Mar. 13, 1951 KBSORBER'FOR VE GEES tea"banishment mesa -lin t.lnca n tonts a, En nd .as snors t Levitation Limited, Leamingtonspa, England nitiate-rise tease 1s, is'ia stnaritmiwires working space thefannul-ar "chamber below the piston head between the wailsloi the plungenand cylinder, and in which direct passage 'of fluid past the piston :head is prevented by a sealin device. which .acts also as "a valirerto 'per nitpasr sage of fluid from either side bi the piston head .to a space the cpnn'e'cfiionfof which tofeifihfi lfif the working spaces i's'selectively controlled by adr ditional valve means. Such unitsare hereinafter called units of the kind referredto,

According to the invention, in a ofthe kind referred to the sealing device Q0 ring .of rubber oilike flexibiejand ,resi terial mounted in a circumferentialgi py a ;the piston head,thelgrobvefbeingpofrniected by passages with "an *internalrecess in the iston head in which the additional valve means are located, and the ring being formed with two lips one of which co-oper-ates with one side ofthe groove and the other with the otnerg igese arat st pair of one way valves each (panell ng the connection between the Working dliaic'e and the internal recess. t. V. s, The T n J's prefer bly substanti y Iii-she e in crosssection withthe basedof ,the U forming line. n e on is. hereinafter. ribed, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a pneumatic suspension device for a motor vehicle which incorporates the invention, the plunger of the said device being shown in elevation; and

Figure 2 is a longitudinal section, on an enlarged scale, through the plunger head of the device shown in Figure 1.

Referring to the drawings, which illustrate a pneumatic suspension device similar to that described with reference to Figures 1 to 3 of the drawings of British Patent Specification No. 570,813, the device comprises a cylinder [0, and plunger II, the plunger having a piston head l2 which fits slidably in the cylinder, and projecting f; at m 'ndcrftrie than,

,Theplunger is tubular, andis clamped between ,thep'istonlhea-d 1 27am anodter .enid closure 111318 15 byfa centralstein i5 .screw-threadediat end tbie sa e stirewsthrcaded.sockets-in the piston head and plug. 1 tThelworkin'g spaces oithedevic are the space il'betweenthe cylinderghead is and-the piston head !2, and the annular space J18 around thesplunger, between the piston head 12 and theme-climati .n. co-axial. .LIEGGS'S il a new in retinitis hejadgtzs opening into the workingspacell and,

sliidabie in the-sameness. a Valvernembr ,zn one. cndjof. which is exposed Ito..=the pressure the. w rking, space 11 slthe recess. being'connected to the-said. workin space'byapassage, '2 LZof small diameterhwhiczh extends, through a stem 2'2 mountedzmtnevalve ineinben c ..,.TVVTQ rings'gqfl lf iiidialcfpoiilstidad from the H8: ipheral ssurf-acelpi the pistonsheadA-Z. into the recess i tsthe ringgni: ports. 23 hearer toM-the avor g space :at their outert end's into .@11 ,C'Jimifi1eni ial groove- 224 inllth'e. piston h art/mi t. the other ring :oinorts 52 igopen into f iiel-ieved-"portidns lfi ,Of the peripheral isuriace iii the head. .j Radial ;,s1oit"s .arefcrmedin, the end ba he cad which iacesltiieworkins space 34 Land L I is termed with-a circumfer; ential D9 h c iha's alwidth equal togthe di tenpe between the pmximateledges otthe parts sit on, hus zcpnnectst the portals, to; .eith'en the per-ts :25, or jthewslptsll spring-2d is prbvide'd w i h.ag sbnihe yalv ember 23. and tends to .keepii substan ially iujthcmiddleiposition. l

In theijgroovelfl. there; .mounted :a ,sealinggdeg la n the, ion-r1 t air n 'ofr iu 1 111K?! lie blegand rcsilicntgmQMQZiQi-I; the. being 101 substantially U-shape in cross section, the base part of the U, which forms the outer peripheral part of the ring, being of considerable thickness, whilst the sides taper towards their extremities, and form radially inwardly directed lips which are much more flexible than the base. As shown, the ring is of progressively decreasing thickness from the centre of the base of the U to the ex-' tremity of each lip. The sides of the U-shaped ring bear on the side Walls of the groove, against which they are urged by pressure acting within the groove, so that the ring prevents outward fiowiqf fluid from the ports 23 into either of the working spaces, but allows flow from either of the working spaces into the ports 23.

The plug I forms a socket for a ball-headed pin 3| by means of which the plunger is attached to one of the members between which the suspension device is mounted, and a flexible boot 32 of 7 rubber or like material, through which the pin 3| extends, encloses the part ofthe plunger which projectsfrom the cylinder. A stem 33 projecting through the cap l4 provides a mounting for the cylinder, the stem 33 being passed through a hole in a flat mounting bracket 34 and retainedbyna nut 35, two rubber discs 36 being'placed one-on ing space l8 until the pressure in the space H .A suspension device for vehicles comprising a each side of the bracket to give flexibility to the" mounting. which enter the hole in thebracket 34. The

fluid used in the suspension device is air, andan The discs 33 have short spigots'3l inflation valve 38 is provided-in the stem- 33 through which air can be pumped into'the device.

The device operates in the following manner.

cylinder, a plunger including a piston head slida'ble in said'cylinder and the plunger having a stem projecting through one end of said cylinder, said piston head defining, within said cylinder, an annular working chamber surrounding said plunger stem, and a cylindrical working chamber on the side of saidpiston head opposite to the plunger stem; a recess in said piston head open to When a vehicle on which the suspension is pro---- vided by a plurality of such devices is stationary, oris travelling on a perfectly smooth surface','the plungers take up a position in the cylinders such that the air pressure in the devices just supports the weight of the vehicle. If a wheel strikes a bump in the road, and is lifted, the. plunger in the suspension device between that wheel and the body of the'vehicle rises, increasing the air pressure in the working'space l1. As the recess I9 is connected to .the'space I! only by the narrow passage 2! the pressure in the recess rise much more slowly than the pressure in the space ll, landthe valve member is therefore displaced into the recess, allowing fluid to pass from the working space ll into'the working space l8, the

fluid passing one lip of the ring 39 and flowing the ring from-the working space IB i'nto the ports" 23, and can flow through the groove-28 and slots 21 into the working space II. The device thus returns smoothly to its-static position.

"If a wheel of the vehicle drops into a pothole or' like depressiomthe plunger moves downwardly, and the pressure in the working space ll falls, so that the valve member .20 moves upwardly, 7 and {fluid from the space 18 flows past the lower lip of the ring 39, through the ports 23,=groove 28 and slots 2'! into the working space IL- W hen the plunger ceases to move downwardly, andtnds to return, air is"prev'ented by the non-return valve action of the ring 30,-f-ron1 re'turning to the work- LII the cylindrical working chamber, a valve member slidable in said recess and urged inwardly of said recess by fluid pressure in said cylindrical working chamber, means in said recess acting to urge said valve member outwardly, passage means in said piston head connecting said annular working space to said recess, a circumferential groove surrounding said piston head, additional passage means' in'said piston head connecting said circumfrential groove to said reces between the passage means connecting the annular working space to said recess and the open end of the recess, a circumferentialrecess.in said valve member adapted, on displacement of said valve member to either side .of a mean position, to provide communication between said additional passage means and said cylindrical working space and said annular working spacerespectively, and a sealing device in said circumferential groove comprising an imperforatering of flexible and resilient material bearing against the cylinder wall, two inwardly deformable lips being provided on said ring one of which co operates with one side of the groove and: the other of which co-operates with the other side of the groove to provide a pair of one-way valves each controlling communic'ation between one working space and the recess in the piston' head by way of the additional passage means.

PETER WARBORNTHORNHILL.

CLIVE KUSTIN GOSLING.

1-. pREFERENCES CITED The following references are of record in the 'file of this patent: c I

UNITED STATESPATENTS 7 Date Number Name 1,612,039 Miller Dec. 28, 1926 1,899,271 Hammond Feb. 28, 1933 2,098,398 Marcier Nov. 9, 1937 2,476,228 Thornhill July 12, 1 949 

